The invention relates to a roller bit for tunnel-driving machines.
Known tunnel-driving machines are equipped with cutting heads and roller bits, which are provided with cutting elements, such as cutting rings carrying cutting pins, and which are formed as one part. These cutting rings are pressed or shrunk onto a cutting body or secured there by means of a retaining ring and groove. Moreover, cutting rollers without cutting rings are known, for which the cutting pins are soldered or shrunk directly into a base body of the roller bit. The cutting rings and the cutting rollers, which are provided with cutting pins, can have different profiles.
It is a disadvantage of the known embodiments that, in the event that a repair becomes necessary, the complete roller bit or its cutting ring must be exchanged as a whole, even if only partial regions of the cutting ring are affected. This causes long repair times, as well as expenses, which cannot be justified, since the roller bit must be dismantled completely from a drilling head, so that such a repair can be carried out.
It is therefore an object of the invention to provide a generic roller bit for tunnel-driving machines which does not have the disadvantages of the known technical solutions.
This objective is accomplished by a cutting ring having at least two or more segments which are fastened exchangeably to the base roller body. By these means, it is possible to replace the cutting ring itself or worn parts of the cutting ring segment by segment, without the previously required dismantling and assembly of a complete roller bit from a drilling head with the therewith associated transporting costs. A total driving time accordingly is minimized by shorter repair times, since the segments of the cutting ring can be exchanged on site. Furthermore, material costs are decreased.
The segments of the cutting ring can be disposed in a specified position by means of profiled guides positively, preferably with a dovetail guide or a T-shaped groove and adapters on a base roller body and connected to the base roller body by means of segment holding devices with a screw thread and/or by means of threaded rings.
The invention is described in greater detail by means of examples.